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Subject: Re: [PATCH v12 20/22] selftests/vm: testcases must restore
 pkey-permissions
References: <1519264541-7621-1-git-send-email-linuxram@us.ibm.com>
 <1519264541-7621-21-git-send-email-linuxram@us.ibm.com>
From: Dave Hansen <dave.hansen@intel.com>
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Date: Fri, 16 Mar 2018 15:32:38 -0700
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To: Ram Pai <linuxram@us.ibm.com>, shuahkh@osg.samsung.com, linux-kselftest@vger.kernel.org
Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, akpm@linux-foundation.org, benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com, ebiederm@xmission.com, arnd@arndb.de

On 02/21/2018 05:55 PM, Ram Pai wrote:
> Generally the signal handler restores the state of the pkey register
> before returning. However there are times when the read/write operation
> can legitamely fail without invoking the signal handler.  Eg: A
> sys_read() operaton to a write-protected page should be disallowed.  In
> such a case the state of the pkey register is not restored to its
> original state.  The test case is responsible for restoring the key
> register state to its original value.

Oh, that's a good point.

Could we just do this in a common place, though?  Like reset the
register after each test?  Seems more foolproof.